1. Field of the Invention
The present invention relates to a method of manufacturing a mask using independent pattern data files, the mask being such as an original mask or a reticle used for exposing an object to radiation such as light, ultraviolet and X-rays that selectively penetrates a pattern on the mask.
2. Description of the Related Art
FIG. 8 is an illustration of a prior art mask manufacturing method. In FIG. 8, patterns are simplified. Pattern data have become tremendously voluminous with the progress of circuit element miniaturization and large-scale circuit. Therefore, various data compression techniques such as a repeated region cut-out method, a hierarchical structure and library data are used for CAD data and data for an exposure system. To effectively compress data, a device pattern 10 and an additional pattern 11 outside the device pattern 10 are separately made, and a mask is manufactured using the data of the both patterns.
FIG. 7 shows a schematic construction of part of a prior art mask pattern producing system.
Data of the device pattern 10 and the additional pattern 11 of FIG. 8 are stored in storage media 20 and 21, respectively. The data of the pattern 11 is produced using a CAD apparatus provided with a computer 30, a display unit 31 and an input unit 32, the latter two of which are connected to the computer 30. The data of the device pattern 10 is produced using a CAD apparatus not shown.
The data in the storage media 20 and 21 are converted to data for an exposure system by computers 33 and 34, respectively, and data for an inspection apparatus to inspect a manufactured mask 13 is also produced. These data are stored on a storage medium 35. The data for an exposure system are loaded into an exposure system 36, a photosensitive material coated on a blank mask is exposed to a radiation, and the exposed material is developed by a developing apparatus not shown to produce the mask 13.
Referring back to FIG. 8, in a scribe region indicated by a scribe pattern 12, there are formed a device identification pattern A12345 for enabling to confirm a used mask pattern by looking a patterned wafer, a pattern for measuring dimensions, a pattern for measuring a resolving power and an alignment pattern for layer-to-layer registration, the latter three patterns being not shown. Patterns not transferred on a wafer in the exposure are formed in a peripheral region outside the scribe pattern, the patterns not transferred including an inspection pattern, an accuracy measurement pattern, a device identification pattern A12345 and an alignment pattern for an apparatus onto which the mask 13 is mounted, for example, a stepper.
The device identification patterns A12345 correspond to the device pattern 10. Therefore, when the device pattern 10 is altered by a design change, the device identification patterns A12345 also change, whereby with respect to not only the device pattern 10 but also the additional pattern 11, the CAD data, the data for an exposure system and the data for an inspection apparatus have to be renewed using the system shown in FIG. 7, resulting in not only increasing the number of manufacturing steps but also reducing reliability.
Further, since the data for an exposure system has the device pattern 10 and the additional pattern 11 independently because of the data compression described above, in a case where the exposure system 36 is of a raster scan type, it is required that not only the device pattern 10 is exposed but also the additional pattern 11 is exposed all over the blank mask. Therefore, it takes a longer useless scanning time for exposure. That is, a region of no need to expose in the additional pattern 11 must be scanned, which reduces a throughput.
Accordingly, it is an object of the present invention to provide a mask manufacturing method which enable to manufacture a mask with a shorter process for data.
It is another object of the present invention to provide a mask manufacturing method which enable to shorten an exposure time by reducing an unnecessary region for raster scan.
In the present invention, there is provided a mask manufacturing method, comprising the steps of: making first data of a device pattern; making second data of an identification and scribe pattern including a scribe pattern surrounding the device pattern, and mask pattern identification patterns formed in a scribe region indicated by the scribe pattern and outside an outer periphery of the scribe region; making third data of an outer peripheral pattern formed outside the outer periphery of the scribe region except the outer one of the mask pattern identification patterns; and producing data for an exposure system or a mask inspection apparatus on the basis of the first to third data, wherein the first to third data are independently made from one another.
If the mask pattern identification pattern outside the outer periphery of the scribe region is included in the outer peripheral pattern, it is required that the identification and scribe pattern and the outer peripheral pattern are to be remade in company with alteration in the mask pattern identification pattern. However, according to the present invention, the mask pattern identification pattern outside the outer periphery of the scribe region is included in the identification and scribe pattern and therefore, only the identification and scribe pattern is required to be remade when the mask pattern identification pattern is altered, which not only makes a process shorter but also makes it possible for an existing pattern to be used with higher reliability than a newly formed one.
The mask pattern identification pattern is, for example, a pattern relating to a device manufacturing process, such as a pattern indicating a process technology or a process line, and in this case, even when the device pattern is altered in the design, the identification and scribe pattern is not required to remake if a change in the identification and scribe pattern does not occur.